This invention relates to a remote control system, and more particularly to an improved remote control system of the type which includes an operator which is adapted to be employed for mechanically operating the throttle of an outboard drive unit and for operating the transmission of the drive unit through an electric motor that is driven on the basis of an electrical signal indicative of the position of the operator and which provides a smooth shifting operation even when the operator is abruptly moved.
Purely mechanical remote control systems have been provided which utilize wire cables and mechanical actuator units to connect the remote operator with a pair of controlled members, such as a throttle and shift actuator, on an outboard drive unit. These types of fully mechanical systems are generally satisfactory for use in smaller watercraft. However, such systems have certain disadvantages when they are used larger watercraft where the distance between the remote operator near the driver's seat and the outboard drive unit itself can be relatively long. The reason for this is that the frictional resistance in the system and operating load imposed on the operator are increased as the length of the cables are increased to accommodate these greater distances. As a result, it is more difficult to effect movement of the throttle and shift actuators over greater distances using purely mechanical systems.
Therefore, a type of remote control system has been proposed wherein the throttle actuator is mechanically connected to the operator while the shift actuator is driven by an electric motor in response to an electrical signal that is indicative of the position of the remote operator. An example of such a system is provided in Japanese Patent Application 2-210228.
Although this type of system decreases the frictional resistance in the system and operating load on the operator, it has certain disadvantages if the operator is moved abruptly. For example, when the operator is suddenly shifted to a forward or reverse position from the neutral position, there will be some time delay before the shift actuator on the outboard drive unit will be actuated. This is due to the time required for processing the electrical signal and actuating the electric motor in response to the operator movement. On the other hand, the throttle actuator, which is mechanically connected to the operator, will be actuated immediately in response to the abrupt movement of the operator. When this occurs, the engine speed will rise while the shift actuator is still in neutral. In fact, by the time the electric motor is actuated to effect movement of the shift actuator, it is likely that the engine speed will have risen to a speed high enough to make it very difficult to bring the shift actuator into gear. Even if the shifting can be accomplished at such a high engine speed, it will usually be a very rough transition and will be accompanied by an abrupt change in engine speed when the drive unit is put in gear.
It is, therefore, a principal object of this invention to provide an improved remote control system which provides for smooth shifting even when the operator of the system is abruptly moved.